MALCOLM Turnbull has secured an agreement with energy retailers, who have promised to write to more customers informing them of better deals.

The Prime Minister met with energy bosses today in Sydney to ensure millions of Australians would be told they can switch to discount plans if required.

"As a result of the action from the two meetings we've now had with the retailers, as many as 2 million Australian families and small businesses could save hundreds of dollars on their electricity bills," he told reporters.

"This is a very big breakthrough, and it's happening here and now. A lot of the things we are doing on energy are long-term, like Snowy Hydro 2.0, but this is helping Australian families now."

Mr Turnbull said energy retailers had agreed to contact customers who were on discounted plans that had expired and "let them know that they were paying more than they ought to and that there are better options available".

"We've secured a commitment from the retailers to provide clearer, more understandable information on the electricity rates that are available, along with the development of a single, simple dollar comparative rates," he said. About one million Aussie households are estimated to be on default packages from their energy retailers, usually more expensive than discounted plans that customers might qualify for if they asked to switch, according to The Australian.

"We've already got commitments from them and I want to confirm those and see how they're tracking in delivering," Mr Turnbull told 5AA radio yesterday.

He said retailers were benefiting from the "inertia" of customers not moving to cheaper plans, as well as the complexity of the system.

Today's meeting will be the second in three weeks. At the first one, retailers agreed to alert customers when a plan was coming to an end and advise them on the consequences of either sticking with the plan or moving to another offer.

He queried calls for the government to help build a new coal-fired power station to address the supply shortage, which is one of the factors driving up prices.

"Certainly the government is not planning to build a coal-fired power station, but I might say ... there is no 'low cost' coal-fired power station, a new one anyway," Mr Turnbull said.

However, he said it would be "good" to have a "state-of-the-art, high-efficiency, low-emission coal-fired power station".